Apparatus for monitoring shuttle filling thread

ABSTRACT

Apparatus for monitoring the motion of a filling thread in weaving machines with shuttles for stopping the weaving machine when there is a break in the thread. The apparatus comprises a signal transmitter in the shuttle having an active electronic component which is influenced by the filling thread passing from the shuttle, a signal receiver positioned outside of said shuttle responding to said signal transmitter for controlling a device for stopping the weaving machine, and means externally of the shuttle for electromagnetically generating electrical energy and supplying it to the electronic component carried by the shuttle.

United States Patent [1 1 Loepfe Apr. 9, 1974 APPARATUS FOR MONITORINGSHUTTLE FILLING THREAD [75] Inventor: Erich Lo epfe,Zollikerberg,

21 Appl. No.: 329,129

Related US. Application Data [63] Continuation of Ser. No. 259,348, June2, 1972, abandoned, which is. a continuation of Ser. No. 869,643, Oct.27, 1969, abandoned.

[30] Foreign Application Priority Data 3,322,162 5/1967 Rydborn 139/3713,688,958 9/1972 Rydborn 139/370 UX 3,676,769 7/1972 Loepfe 139/370 UXFOREIGN PATENTS OR APPLICATIONS 1,473,899 2/1967 France 139/3711,253,647 11/1967 Germany 139/371 OTHER PUBLlCATlONS 1,253,647 11-2-1967German Application (Zentner) Primary Examiner-James Kee Chi Attorney,Agent, or FirmMorgan, Finnegan, Durham & Pine [5 7] ABSTRACT Apparatusfor monitoring the motion of a filling thread in weaving machines withshuttles for stopping the weaving machine when there is a break in thethread. The apparatus comprises a signal-transmitter in the shuttlehaving an active electronic component which is influenced by the fillingthread passing from the shuttle, a signal receiver positioned outside ofsaid shuttle responding to said signal transmitter for controlling adevice for stopping the weaving machine, and means externally of theshuttle for electromagnetically generating electrical energy andsupplying it to the electronic component carried by the shuttle.

10 Claims, 3 Drawing Figures Oct. 29, 1968 Switzerland 16290/68 [52] US.Cl. 139/371 [51] Int. Cl D03d 51/34 [58] Field of Search 139/371, 370;66/163; 28/51; 57/81 [56] References Cited I UNITED STATES PATENTS3,593,756 7/1971 Vella 139/371 3,467,149 9/1969 Dosch et al......138/371 3,613,744 4 10/1971 Dosch et al 139/371 3,298,401 l/l967 Stutz139/371 832% t am,

MENTED APR 9 i974 gum APPARATUS FOR MONITORING SHUTTLE FILLING THREADThis is a continuation, of application Ser. No. 259,348, filed June 2,1972 now abandoned, which in turn is a continuation of application Ser.No. 869,643, filed Oct. 27, 1969, now abandoned.

It is to be understood that the above Abstract of Disclosure issubmitted in compliance with the require ments of the United StatesPatent Office, Rule 72 (b), Rules of Practice in Patent Cases, and isnot to be used in the construction of, or as limiting, the scope of theinvention as hereinafter defined in the Appended claims.

BACKGROUND OF THE INVENTION 1. Field of the Invention Y The presentinvention relates to a filling thread monitoring apparatus for use withweaving machines having shuttles. More particularly, the presentinvention relates to apparatus for supplying electrical energy to theactive electronic component in the signal transmitter of a fillingthread monitoring apparatus independent of a source of such energycarried by the shuttle.

2. Description of the Prior Art In a weaving loom having a shuttle it isnecessary to check whether the filling thread is being drawn from thefilling bobbin, i.e., whether the thread is moving in the space betweenthe filling bobbin and the point where it leaves the shuttle. For thispurpose, the shuttle may carry a signal generator which transmits asignal,

generated by the motion of the filling thread when it runsoff thefilling bobbin, to a signalreceiver. If this signal does not occurduring the sensing interval, the loom is stopped by the signal receiver.

In a filling thread monitor of the type described in the precedingparagraph, the signal generator comprises a. miniature switch and a highfrequency transmitter actuatedby said switch. Electrical energy must besupplied tothe transmitter and also any amplifier circuit associatedtherewith, at least during the desired operating period. Toaccomplishthis, the shuttle may contain a source of current such as a smallbattery or other energy storage means. This solution has substantialdisadvantages, primarily as a result of the small capacity and thereforethe short life of the batteries or storage cells which can be consideredfor this application. Frequent changing and the necessary frequentperiodic inspection of the condition of the built in current source areimpossible when such a device is actually used in a weaving mill unlessthe machinery is first shut down.

In addition, to switch the current source on and off every time it isinspected would also require sophisticated equipment.

SUMMARY OF THE INVENTION vide a filling thread monitoring apparatus witha supply of energy for the signal transmitter which does not re- 'quirefrequent periodic inspection to determine its usefulness.

In accordance with the objects of the invention there is provided afilling thread monitoring apparatus for a thread carrying shuttle of aweaving machine in which the supply of energy is independent of acurrent source carried along with the shuttle. The filling threadmonitoring apparatus of the invention has a signal transmitterpositioned in the shuttle with an active electronic component that isinfluenced by the filling thread. Concurrently the active electroniccomponent is supplied with electrical energy by means of a device alongthe trajectory of the shuttle. For this purpose, the signal transmittercomprises preferably an induction coil which duringthe travel of theshuttle intersects the field of a permanent magnet which is placed,alongside the trajectory of the shuttle.

Also in accordance with the present invention there is provided a signalreceiver positioned outside of the shuttle for controlling a devicewhich halts the weaving machine in response to a predetermined signalfrom the transmitter. 7

By the practice of this invention, therefore, the proper sensing of thethread and operation of the weaving machine are accomplished without thedrawbacks of the heretofore available filling thread monitor.

Additional objects and advantages will be set forth in part hereinafterand will be obvious herefrom or may be learned by practice with theinvention, the same being realized and attained by means of the steps,combinations and improvements pointed out in the appended claims.

Furthermore, the accompanying drawings referred to herein andconstituting a part hereof illustrate the invention and together withthe description serve to explain the principles thereof.

BRIEF DESCRIPTION OF THE DRAWING The invention will be described andunderstood more readily when considered with the attached drawing inwhich:

FIG. 1 shows a part of a shuttle from above, when it is leaving theshed, with a built in signal transmitter, to-

'gether with elements comprising a portion of the signal receiver, shownin cross-section;

FIG. .2 is a front cross-sectional view, partially broken-away, of theelements illustrated in FIG. 1;

- FIG. 3 shows a schematic circuit diagram of a filling The sensing ofthe filling-thread occurs preferably toward the end of the period whenthe filling is placed in the fabric and consists in checking whether thefilling thread is still drawn from the filling bobbin. For this purposethe shuttle carries a signal transmitter which transmits, within adefinite sensing interval, a signal, which is generated by the motion ofthe filling thread when it runs off the filling bobbin, to a signalreceiver. The motion of the filling thread is an unequivocal criterionfor the intact condition of said thread when it is placed in the fabric.If the above mentioned signal does not occur during the sensinginterval, the loom is stopped by the signal receiver.

This concept of filling thread sensing makes it possible to supplyelectrical energy to a signal transmitter comprising an activeelectronic component, for instance an amplifying transistor oroscillator circuit, not continuously but only during the sensinginterval.

Now referring to FIGS. 1 and 2, shuttle 1 is just leaving the shed,which is formed by the warp threads (not shown), moving from left toright with its rear part still above the batten 2 and in front of thereed 3. The thread 5 pulled from the filling bobbin 4 runs through theguide 6 and over a thread sensing means 10, 11 arranged therein, leavingthe shuttle through bushing 7. In the guide 6 the filling thread isdeflected between the two guide bushings 8 and 9 on a fixed smallfriction plate 10, which consists for example of a ceramic materialbased on oxides. Since the friction plate is fixed, the thread travels apath through the guides 8, 9 and over the plate 10, which isessentiallyindependent of the degree of thread tension. Beneath friction plate 10is a small plate 11 made from an electrically conductive material-whichis electrically connected to a circuit consisting of the componentsmounted on plate 12. The space 13 in which the electrical components arelocated, is filled with an insulating potting compound.

The signal transmitter comprises an induction coil 15, which is providedwith an electrically conductive shield 14 inserted in the side wall ofshuttle l facing reed 3, which is part of the electric circuit of thesignal transmitter described hereinafter.

A rectangular induction coil 17 is attached to the batten 2 by means ofthe not completely shown fastening means 16, coil 17 is the actualreceiving means of the signal receiver. Coil 17 is connected by means ofterminals 18 and 19 with the output section of the signal receiver whichwill also be described hereinafter. Terminal l9 carriesthe potential ofelectric shield 20 surrounding coil 17. A permanent magnet 21 is placedinside coil 17 such that pole 22 of magnet 21 is at a greater distancefrom reed 3 and at a smaller distance from the trajectory of shuttle 1than pole 23 which is closer to reed 3, thus providing a traversemagnetic field that varies in strength relative to the direction ofshuttle motion. The permanent magnet 21 is potted inside coil 17.

Now referring to FIG. 3, the circuit contains first the signaltransmitter, located in shuttle 1, consisting the components 11, 24, 25,26, 27 and 15. In this circuit, the above mentioned conductive plate 11is connected through a capacitor 24, with a capacity for example ofseveral uF, with the control electrode (gate) of a field effecttransistor 25. The input circuit of transistor 25 contains a resistor 26of approximately 10 megohms, while the drain source circuit contains aninduction coil 15 and a diode,27 which are connected in parallel.

The signal receiver comprises the induction coil 17 and a circuitrepresented by the elements 28 to 36 whose purpose and function will bedescribed in more detail below. The elements 37 to 40 are for thepurpose of stopping the weaving machine and will also be described inmore detail below.

In operation, the intact filling thread 5 runs from the bobbin 4 overthe friction plate 10 in the guiding section 6 of shuttle 1. shortvariations in the electric potential are generated trilmelectrically.i.e., by frictional generation of electricity in the small conductiveplate 11 which arrive, through capacitor 24, at the control electrode ofthe field effect transistor 25. The electrical energy supplied totransistor 25, which acts as an amplifier, is obtained from the kineticenergy of shuttle 1 when it passes permanent magnet 21. If the coil 15moves, in particular when the shuttle leaves the shed, past magnet 21,an electromotive force is induced whose shape is, due to the spatialarrangement of the magnet shown in FIG. 1, that of an extended flatpulse, followed by a short, steep pulse of the opposite polarity. Theflat pulse, which is generated in the coil by the steady increase of themagnetic field from the time it enters the field to the time it leavesthe area of pole 22, supplies the voltage required for operation oftransistor 25, while particularly high voltage peaks of the oppositepolarity are by-passed through the diode 27 in order to protecttransistor 25.

The time when the voltage pulse occurs determines the time when thefilling thread 5 is checked. If the filling thread is intact at thattime, the variations in potential on the control electrode of transistor25, which were mentioned above, will cause a modulation of the currentflowing through coil 15. Due to the inductive coupling of coils 15.and17 during the passage of shuttle 1, corresponding voltage variationswill be generated at input terminals 18, 19 of the signal receiver,which contain frequency components in the range between approximately 5kilocycles and 50 kilocycles.

On this signal voltage will be superimposed at terminals 18, 19 thevoltage pulses which are generated by the inductive transmission to coil17 of the transistor operating voltage induced in coil 15. In the lattervoltage pulses the low-frequency components with freqas i s aapp y 1 klo ysls prss qminats- The total of the voltage variations generated atterminals 18, 19 is first amplified in amplifier 28 and then fed tofilters 29 and 34. Filter 29 is a high-pass filter and its purpose is toseparate the part of the signal which signifies the running of thread 5from the total voltage variations, for example the frequencies abovekilocycles, and to feed these frequen cies to amplifier 30. Filter 34 isdesigned as a low-pass filter, for instance with a cutoff frequency of500 cycles to l kilocycle and is used for separating and passing thelow-frequency components which characterize the pulses of the supplyvoltage.

Filter 34 is followed by a pulse-shaper 35 which is triggered by thepositive voltage pulse induced by the front of the supply voltage pulseand which generates a square pulse of predetermined length which is alittle shorter than the length of the supply voltage pulse. This squarepulse is fed into coincidence network 36 at whose second input terminala signal pulse arrives simultaneously if the thread is running offbobbin 4 properly. The signal pulse is generated in the following mannerby the circuit shown in FIG. 3: The high-frequency voltage variations atthe output terminal of filter 29 are greatly amplified (block 30) andcompressed (block 31). The signal which emerges has very steep fronts.By subsequent full-wave rectification (block 32) and smoothing in alow-pass filter (block 33) a pulse of practically constant height isobtained whose length corresponds to the length of the high-frequencyvariations of the signal voltage.

The simultaneous occurrence of the signal pulse and of the correspondinggate pulse generates at the output terminal of coincidence circuit 36.This pulse, which confirms that the filling thread was not broken at theinstant of sensing, actuates elements 37 to 40 which can trigger thestopping of the loom.

For this purpose the output pulse of coincidence circuit 36 is fedinto'one of the input terminals of the anticoincidence network 37 whosesecond input terminal is connected to a pulse generator 38. Logicnetwork 37 causes a conjunctive combination of the input signals, butwith a negation of the first input. Logic network 37 delivers an outputpulse only if a pulse arrives at the second input terminal and there isno signal arriving at the first input terminal at the same time.

Pulse generator 38 is driven by the drive mechanism of the weavingmachine, for example by means of a control cam attached to thecrankshaft which carries a small permanent magnet on its peripheryacting on a stationary induction coil. The phase angle of the triggeringpulse generated by pulse generator 38 is chosen in such a manner inrelation to the operating cycle of the weaving machine, that thistrigger pulse arrives at anti-coincidence network 37 simultaneously withthe signal pulse generated by coincidence network 36 which, when thefilling thread 5 runs off normally, arrives at the instant when shuttle1 leaves the shed. Anticoincidence network 37 then delivers no outputpulse. If the filling thread is broken, however, the signal pulse atcoincidence network 36 is missingwhen the triggering pulse arrives frompulse generator 38 and the anticoincidence network 37 then generates anoutput pulse. This pulse causes stopping of the loom through a relaydevice 39 and the actual tripping circuit 40 which contains, forinstance, a tripping solenoid.

It is important that in the circuit shown in the drawing, the shuttingoff of the loom always takes place when the signal, which indicatesproper running-off of the filling thread, is missing, and also if thesignal transmitter or receiver are not functioning properly. By couplingthe triggering pulse with the drive mechanism of the loom we are alsoassured that the sensing interval is defined with relation to thetrajectory of the shuttle. The filling thread is to be sensed at theinstant,and only at the instant, when the shuttle emerges from the shed.The passage of the shuttle past the signal receiver when it enters theshed has no effect on the tripping circuit, as no triggering pulse isgenerated at that instant. In

order to obtain complete monitoring of the filling thread, an analogousdevice consisting of receiver coil and permanent magnet,exactly as shownfor one side It should also be mentioned that FIG. 3 shows only thecomponents which are important for explaining the functioning of thecircuit. In order to simplify the drawing, the intermediateamplification and delay stages, which are obvious to the expert, havebeen omitted.

Such intermediate stages are, for example, provided to.

assure that the input pulses of the coincidence and anticoincidencenetworks, 36 and 37, normally coincide, even ifthe dispersions in timeand space due to the functioning of the weaving machine are taken intoaccount.

. The transmission of the energy required for the operation of thesignal transmitter in the flying shuttle can, in principle, also takeplace by means of electrical or electromagnetic fields. Amongst thelatter fields, the

greatest practical importance can probably be assigned to a beam oflight rays cooperating with a photoelectric converter in the shuttle.

Preferably a magnetic field is used, however, for the transmission ofenergy, either in theform of a static field, as in the above describedcase of a permanent magnet, or as an alternating field, such as thefield created by an induction coil. The frequency of the alternatingfieldis then chosen in such a way that it can be clearly separated inthe receiver from the frequency band of the signal voltage variations.

Another embodiment is characterized in that the transmissions of energyand signal are separated in time. In this design, the electro-motiveforce which is induced in a coil in the shuttle causes, for instance,the charging of a capacitor which serves as an energystorage device upto the instant when the signal is transmitted. Such storage permitsspatial separation of the elements used for the transmission of energyand of those used for the'transmission of the signal. The shuttle may,for example, carry one coil each for the reception of energy and for thetransmission of signals, respectively, in its two ends, or in one of itsends and in one side wall. In the output circuit of the transistor thesignal transmitting coil is then connected in series with 'a storagecapacitor, and parallel to said capacitor is circuit containing theenergy receiving coil and a rectifier, connected in series.

The advantages of the energy transmission to the signal transmitter inthe shuttle, in accordance with the invention, have a. decisiveeffect,.mos t importantly in the practical operation of such a fillingthread sensor. The signal transmitter requires neither maintenance norinspection; its ability to operate correctly does not depend on anyshort lived component, but it is always ready to operate. The fillingthread monitor described above, represents, in addition, a substantialsimplification ofthe equipment, as the transmission of energy and thetransmission of signals can beeffected by a combined device on theweaving machine.

What is claimed is: l I 1. In apparatus for monitoring the motion of afilling thread in a shuttle of a weaving machine, the apparatus havingsignal transmitting means carried by the shuttle for developing a signalrepresenting the condition of the thread, and signal responsive meansphysically independent of the shuttle and responsive to the signaltransmitter, the combination of:

triboelectric sensing means mounted'in the shuttle immovablyfordeveloping electrical potential variations comprising a sensingsignal representing movement of the thread through the shuttle; thetransmitting means including electronic means carried by the shuttle foramplifying the sensing signal to a levelsuitable for transmission; andelectrical energy supplying means including a first device positionedadjacent the shuttle trajectory and a second device carried by theshuttle, the first and second devices being electrically cooperative togenerate and supply electrical energy to the electronic amplifying meansupon passage of theshuttle by-the first device. 2. The apparatus ofclaim 1, wherein the energy supplying means includes:

a magnetic device for developing a magnetic field traversing thetrajectory of the shuttle; and

means carried by the shuttle for electromagnetically interacting withthe magnetic field to develop an electrical potential signal supplied tothe amplifying means.

3. The apparatus of claim 2, wherein:

the interactive magnetic field varies in strength relative to thedirection of the shuttle trajectory.

4. The apparatus of claim 3, wherein:

the weaving machine includes a batten; and

the magnetic field means comprises a permanent magnet attached to thebatten disposed to have a magnetic axis angularly related to thetrajectory.

5. The apparatus of claim 1, wherein:

the electronic amplifying means comprises a semiconductor amplifier; and

the energy supplying means is effective to develop an electrical pulseof sufficient magnitude and duration to cause the semiconductor, deviceto conduct and thereby amplify the generated electrical signal suppliedthereto during the occurrence of the pulse.

6. The apparatus of claim 1, wherein:

the sensing means comprises a friction element and an electricallyconducting element associated therewith for developing the generatedelectrical signal.

7. The apparatus of claim 1, further comprising:

means carried by the shuttle for temporarily receiving and storingelectrical energy to be supplied to the amplifying means by the energysupplying means.

8. The apparatus of claim 6, wherein:

the friction element is made of oxide ceramic material.

9. The apparatus of claim 1, further comprising:

means fixedly mounted in the shuttle for guiding the moving fillingthread in a path adjacent the sensing means, said path being independentof the tension of the thread.

10. In apparatus for monitoring a filling thread carried by the shuttleof a weaving machine and including means for producing a signalrepresenting the condition of the thread, a signal transmitter in theshuttle, and a signal receiver positioned to receive the signal from thetransmitter:

sensing means for generating an electrical signal having potentialvariations related to movement of the filling thread through the shuttleand substantially independent of the degree of tension of the thread;

ac'tive electronic means carried by the shuttle and electrically coupledto the transmitter for amplifying the electrical signal to betransmitted; and

means including an element carried by the shuttle and a devicepositioned adjacent the trajectory of the shuttle, such element anddevice being electrically cooperative to supply electrical energy to thesignal amplifying means upon movement of the ,s qt ls e n?!-

1. In apparatus for monitoring the motion of a filling thread in ashuttle of a weaving machine, the apparatus having signal transmittingmeans carried by the shuttle for developing a signal representing thecondition of the thread, and signal responsive means physicallyindependent of the shuttle and responsive to the signal transmitter, thecombination of: triboelectric sensing means mounted in the shuttleimmovably for developing electrical potential variations comprising asensing signal representing movement of the thread through the shuttle;the transmitting means including electronic means carried by the shuttlefor amplifying the sensing signal to a level suitable for transmission;and electrical energy supplying means including a first devicepositioned adjacent the shuttle trajectory and a second device carriedby the shuttle, the first and second devices being electricallycooperative to generate and supply electrical energy to the electronicamplifying means upon passage of the shuttle by the first device.
 2. Theapparatus of claim 1, wherein the energy supplying means includes: amagnetic device for developing a magnetic field traversing thetrajectory of the shuttle; and means carried by the shuttle forelectromagnetically interacting with the magnetic field to develop anelectrical potential signal supplied to the amplifying means.
 3. Theapparatus of claim 2, wherein: the interactive magnetic field varies instrength relative to the direction of the shuttle trajectory.
 4. Theapparatus of claim 3, wherein: the weaving machine includes a batten;and the magnetic field means comprises a permanent magnet attached tothe batten disposed to have a magnetic axis angularly related to thetrajectory.
 5. The apparatus of claim 1, wherein: the electronicamplifying means comprises a semiconductor amplifier; and the energysupplying means is effective to develop an electrical pulse ofsufficient magnitude and duration to cause the semiconductor device toconduct and thereby amplify the generated electrical signal suppliedthereto during the occurrence of the pulse.
 6. The apparatus of claim 1,wherein: the sensing means comprises a friction element and anelectrically conducting element associated therewith for developing thegenerated electrical signal.
 7. The apparatus of claim 1, furthercomprising: means carried by the shuttle for temporarily receiving andstoring electrical energy to be supplied to the amplifying means by theenergy supplying means.
 8. The apparatus of claim 6, wherein: thefriction element is made of oxide ceramic material.
 9. The apparatus ofclaim 1, further comprising: means fixedly mounted in the shuttle forguiding the moving filling thread in a path adjacent the sensing means,said path being independent of the tension of the thread.
 10. Inapparatus for monitoring a filling thread carried by the shuttle of aweaving machine and including means for producing a signal representingthe condition of the thread, a signal transmitter in the shuttle, and asignal receiver positioned to receive the signal from the transmitter:sensing means for generating an electrical signal having potentialvariations related to movement of the fIlling thread through the shuttleand substantially independent of the degree of tension of the thread;active electronic means carried by the shuttle and electrically coupledto the transmitter for amplifying the electrical signal to betransmitted; and means including an element carried by the shuttle and adevice positioned adjacent the trajectory of the shuttle, such elementand device being electrically cooperative to supply electrical energy tothe signal amplifying means upon movement of the shuttle therepast.